Treatment of keratinous fabrics and fibres



United States Patent 3,046,080 TREATMENT OF KERATINOUS FABRICS AND FIBRES Alan William Holmes, Walton-on-Thames, England, as-

signor to Lever Brothers Company, New York, N.Y., a corporation of Maine No Drawing. Filed Feb. 1, 1960, Ser. No. 5,656 Claims priority, application Great Britain Feb. 5, 1959 5 Claims. (Cl. 13-128) This invention relates to the treatment of keratinous fibres and of fabrics containing or consisting of keratinous fibres.

These fibres contain disulphide (SS-) linkages,

- which are present as cystine residues in the keratin molecule and which cross-link the long protein chains thereof. Keratinous fibres can be set in a desired shape by treating them under conditions such that these disulphide cross-linkages become broken, with formation of mercapto (SH) groups, in the form of cysteine residues. The protein chains are then able to re-align themselves; and while the fibres are held in the desired shape, fresh cross-bonding forces-not necessarily those associated with --SS-- linkages-are developed which cause the fibres to persist to a greater or less extent in the desired set after their release from constraint. Processes of this kind are used for the treating of wool fabrics, steam being used to break the disulphide cross-linkages. Setting can be made more permanent by using steam in the presence of sulphur dioxide or a volatile base such as ammonia, or a volatile salt thereof such as ammonium sulphite. Breaking of the disulphide cross-linkages can also be effected by aqueous solutions of salts of thioglycollic acid.

The present invention is concerned with treating keratinous fibres before their submission to such a setting process, in order to improve the set. It has now been discovered that improvement in the set can be achieved by an esterification process carried out before breaking the disulphide linkages of the keratinous fibres. The nature of this improvement varies, of course, with the setting process itself; thus the invention can be used to treat keratinous fibres in the form of a fabric to improve the extent to which the set imparted to the fabric by ordinary steam treatment persists on washing, or to improve the sharpness of creasing or pleating imparted by steam used in conjunction with sulphur dioxide or a volatile base or volatile salt thereof, or to improve the tightness of pleating obtained by treatment with aqueous thioglycollate solutions. It can be used to treat keratinous fibres which are not in the form of a fabric to improve the tightness of waving imparted by permanent waving processes.

The mechanism of this process may be this: salt links are known to exist between the protein chains present in keratinous fibres, being formed by the association of carboxylic acid groups with amino groups which are present on the protein chains; esterification of the carboxylic acid groups breaks these links. A more relaxed molecular structure might thus be obtained, so that when the disulphide linkages are broken during the subsequent setting process and the chains re-align themselves, this re-alignment can take place more easily, unhampered by salt links.

The process of the invention is accordingly one for the treatment of keratinous fibres, in which the fibres are contacted with an esterifying agent for carboxylic acid groups under esterifying conditions. The treated fibres are then subjected to a setting process.

Preferably, the esterifying agent employed is an alcohol. Suitable alcohols are those of low molecular weight, especially methanol, ethyl alcohol, n-propanol ICC and isopropanol. When using an alcohol, esterifying conditions can be provided by the presence of an acid catalyst, for instance hydrochloric acid, and elevated temperature, suitably above 50 C. It is convenient to operate at the boiling point of the alcohol employed, to achieve rapid esterification.

Suitable keratinous fibres for the treatment are wool and hair.

The setting process applied after the treatment can be one in which a mercapto compound is employed to break the disulphide linkages; thioglycerol can be used for this purpose, but thioglycollates, for example, ammonium thioglycollate, are most suitable. Thus, a fabric can be formed to the shape desired and impregnated with or immersed in boiling aqueous thioglycollate solution; or cold thioglycollate solution can be employed, and in this case the formation of fresh cross-bonding forces is brought about by addition of an oxidising agent, such as sodium perborate, in a manner analogous to that adopted in the cold permanent waving of hair. Alternatively, the setting process applied can be that entailing the use of steam.

The invention is illustrated by the following examples.

Example 1 A switch of hair more than 20 cm. in length and of weight 3 g. was suspended in methyl alcohol (150 cc.) to which a small amount of concentrated hydrochloric acid (3 cc.) had been added. The suspension of hair was then refluxed for hour.

After rinsing in water, the treated hair was wound on to a peg board containing 10 pegs equidistantly spaced in two lines 1 cm. apart, the distance between adjacent pegs in one line being 9.5 mm. The hair was next treated with an 8.8% by weight aqueous solution of ammonium thioglycollate at pH 9.6 and allowed to stand for 30 minutes at room temperature. It was then neutralised with a solution of 5 g. sodium perborate tetrahydrate in water (500 cc.). After this solution had penetrated the hair, the hair was unwound from the peg board, thrown into cold water, and allowed to take up its new permanent shape. The distance between the four crests of the waves thus obtained was measured.

A similar switch of hair which had not been submitted to the esterifying treatment was subjected to a similar permanent waving process on the peg board, and the average distance between the four crests of the waves again measured.

For perfect conformation to the shape provided by the peg board, the distance between the four crests would be 29 mm: the distance between these crests when the esterifying treatment had been used was only 42 mm, while when only the permanent waving treatment had been employed, the distance was 60 mm. The relaxation occurring in the treated hair when it was placed in water was thus reduced from 31 mm. to 13 mm. by using the process of the invention, so that the waves produced were tighter.

Example 2 A piece of undyed wool fabric of weight grams and area 7,000 cm. was kept immersed for A1 hour in a boiling mixture of 5 litres of industrial methylated spirit (that is ethyl alcohol containing about 5% of methyl alcohol) and 140 cc. of aqueous 10 N hydrochloric acid.

The fabric was then removed from the esterification medium, washed in water, and. dried in air.

Samples of fabric were then submitted to setting processes as follows:

treated according to the invention) was formed into 9 aoaaoao 3 pleats, and then steam pressed in the conventional manner for 2 minutes to set the pleats.

A piece (30 x 5 cm.) of fabric treated under esterifying conditions as described above was similarly set in pleats.

Each pleated piece was first allowed to stand for 24 hours in air at 24 C. and 65% relative humidity, and then suspended vertically by one end under its own Weight. Its length S was then measured.

The degree of permanence of the pleats was then assessed as follows:

Each piece was immersed for 16 hours in an aqueous solution containing 0.3% by weight of a sodium secondary long chain alkyl sulphate wetting agent and 0.3% by weight of sodium sesquicarbonate. The initial tempera ture of the solution was 40 C. After 16 hours had elapsed, each piece was removed from the solution, rinsed with water, and allowed to dry, unstressed, in air at room temperature. It was then maintained for 24 hours at 24 C. at a relative humidity of 65%. It was then suspended vertically from one end under its own weight,

and its length (W measured.

The degree of permanence (P) of the pleating is measured by 100 (30W )/(30S Results were:

Fabric subjected to steam pressing only: P=29 Fabric subjected first to esterification conditions, then to steam pressing: P=70 A piece (30 x 5 cm.) of the original fabric was formed into '14 pleats, sprinkled with 5% of its weight of ammonium carbonate, and then steamed for 2 minutes to set the pleats. (This procedure is described in British Patent Specification 775,486.) A piece of the fabric treated under esterifying conditions was similarly set in pleats.

The degree of permanence of the pleats thus obtained was substantially the same for both untreated and esterified fabrics, but the pleats formed in the esterified material were much sharper.

What is claimed is:

1. A process for the setting of keratinous fibres which comprises subjecting the fibres to an esterification treatment with an alcohol at elevated temperature in the presence of an acid esterification catalyst before submission to the setting operation.

2. A process for the setting of a fabric consisting of or containing keratinous fibres, said process comprising subjecting the fabric to an esterification treatment with an alcohol at elevated temperature in the presence of an acid esterification catalyst, and subsequently submitting the fabric to .a setting operation.

3. A process according to claim 1, in which the alcohol is selected from the group consisting of methanol, ethanol, propanol, and isopropanol.

4. A process according to claim 1, in which the catalyst is hydrochloric acid.

5. A process according to claim 1, in which the keratinous fibres of the fabric are wool.

References Cited in the file of this patent UNITED STATES PATENTS 2,740,727 Littleton et al. Apr. 3, 1956 2,876,781 Martin Mar. 10, 1959 FOREIGN PATENTS 775,486 Great Britain May 22, 1957 799,432 Great Britain Aug. 6, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent. No, 3,046 O80 July 24 1962 Alan William Holmes It is hereby certified that error appears in the above numbered pat-- ent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 40, for "flbres" read fibres column 2 line '71 for "not" read n o t column 4 v lines 17 20 and 22, for the claim reference numeral "1'', each occuymrence read 2 Signed and sealed this 13th day of November- 1962.

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Commissioner of Patents Attesting Officer 

1. A PROCESS FOR THE SETTING OF KERATINOUS FIBRES WHICH COMPRISES SUBJECTING THE FIBRES TO AN ESTERIFICATION TREATMENT WITH AN ALCOHOL AT ELEVATED TEMPERATURE IN THE PRESENCE OF AN ACID ESTERIFICATION CATALYST BEFORE SUBMISSION TO THE SETTING OPERATION. 